1. Field of the Invention
The present invention relates to a surgical ventilating apparatus for protecting members of surgical teams from potentially harmful products that may issue from an operating zone.
2. Description of the Prior Art
Since the advent of the discovery that bacterial and other microorganisms cause diseases and that such microorganisms are easily transmitted to a patient's incision from such sources as a carrier doctor, an unclean instrument or even the air, hospital operating room procedures have incorporated methods to protect the patient by preventing contamination of the operating field. In particular, sources of patient contamination have included bacteria and other microorganisms shed or exhaled by members of the operating team. For example, traditional protective measures have included that the operating team wear face masks. Such protective measures also have included use of ventilating systems that function to prevent contaminants (shed or exhaled by members of the operating team) from entering the surrounding atmosphere and, in particular, from entering the operating field. For example, U.S. Pat. No. 4,055,173 discloses a system for drawing air exhaled by a surgeon and the like away from the surgeon's face so as to limit contamination of the patient.
Although the prior art has included numerous measures to protect patients from contamination originating with the members of the surgical team, there have been few improvements in the prior art to help protect members of the surgical team from airborne contaminants and the like originating with that portion of the patient exposed in the operating field.
Contaminants of concern to members of surgical teams can and do include the Acquired Immunodeficiency Syndrome (AIDS) virus, a disease for which there is currently no effective cure. Thus, the risk of contracting AIDS has created substantial new and deadly problems for the surgeons and other operating room staff. Further, the current spreading epidemic of AIDS has imposed serious health risks on other health care workers subjected in any way to AIDS contaminated blood and body fluids. However, such risks are particularly high for surgeons in all subspecialties and for other operating room personnel, since many operations require drilling, reaming, cutting or like processes and such processes create an aerosol of the patient's blood, tissue, bone or the like that becomes airborne. Aerosols of this type contain live virus, including AIDS virus, when such is present in the patient.
Once a contaminated aerosol subsequently settles on a mucus membrane or open wound of a doctor or nurse, they may be infected by the virally transmitted disease (including AIDS). Accidental contamination with airborne aerosols of blood and body fluids of patients having other diseases, such as hepatitis B, may also be communicated by such a mechanism.
Studies have also identified other sources of risk to include inadvertent inoculations through scalpel laceration, needle puncture, splashing and contact of contaminated serum or body fluids with an open wound. Such studies are described in J. Bartlett, "Testing for HIV Infection: Recommendations for Surgeons", Vol. 73, No. 3, American College of Surgeons Bulletin and G. Telford, et al., "A Protocol to Reduce the Risk of Contracting AIDS and Other Blood-Borne Diseases in the OR", March, 1988, Surgical Rounds for Orthopedics.
In addition to the traditional measures for protecting patients noted above, guidelines have been proposed to safeguard health care workers in the high risk areas. These guidelines consist mainly of recommendations for safe handling of sharp instruments and also include barrier precautions such as gloves, face shields, impervious masks and gowns, and foot and leg wear. However, such guidelines do not adequately address the risk associated with the effects of spraying blood and the like and the aerosolization of blood, body fluids and tissue during a medical procedure. The production of such aerosols occurs during surgical procedures involving the use of many medical operating tools (especially rotating or sawing power equipment such as high speed drills, saws and reamers of the type used by orthopedic surgeons, neurosurgeons and other surgeons who must penetrate bone and other tissue). While the extent and effects of aerosoled blood, body fluids and tissue during surgical procedures is dependent upon the size, shape and speed of the spray inducing devices, often the microscopic aerosols are found in the air throughout the operating room.
Other safeguard guidelines suggest that preoperative testing be conducted for a presence of risk-producing contaminants. Such testing would, it is thought, by identifying such contaminants, allow surgeons to take special precautions. However, preoperative testing for patients inflicted with the human immunodeficiency virus (HIV), AIDS related complex (ARC) and hepatitis B has encountered legal constraints and is also not always effective in operation. Legal constraints against preoperative testing have arisen because of the controversial nature of such testing. Preoperative testing is also not always effective because of the existence of a "serum negative window" (i.e. early period in the disease cycle when the disease is not easily detectable) between exposure and the time when the virus produces sero positive test results. Further, in emergency situations where low but significant percentages of trauma victims are sero positive there is often no time for preoperative testing. And even if testing does show a positive virus infection of AIDS or a similar disease, the surgery may still require a procedure that will produce an aerosol containing the virus.
Accordingly, it is highly desirable to confine the potential contaminant to the smallest area possible and, thus, minimize its diasemination and ultimate spread to members of the surgical team and other health care workers. This can be accomplished by creating a negative pressure zone in the field of operation which operates to remove the contaminants before they escape into the surrounding atmosphere. For this purpose, it is important that the low pressure zone be generated by a device which is near the wound or incision in the field of operation but which does not impede the dexterity or vision of the surgeon.